static void Main(string[] args)
{
Console.WriteLine("Day 21 - Allergen Assessment");
Console.WriteLine("Star 1");
Console.WriteLine();
List <Food> foods = File.ReadAllLines(inputFile)
.Select(x => new Food(x))
.ToList();
List <string> allergenTexts = foods
.SelectMany(x => x.allergens)
.Distinct()
.ToList();
HashSet <string> uniqueIngredients = new HashSet <string>(foods.SelectMany(x => x.ingredients));
List <Allergen> allergens = new List <Allergen>();
foreach (string allergenText in allergenTexts)
{
Allergen allergen = new Allergen(allergenText);
foreach (Food food in foods.Where(x => x.allergens.Contains(allergenText)))
{
allergen.AddIngredientCollection(food.ingredients);
}
allergens.Add(allergen);
}
bool finished = false;
HashSet <Allergen> figuredOutAllergens = new HashSet <Allergen>();
while (!finished)
{
finished = true;
foreach (Allergen allergen in allergens)
{
if (allergen.IsFiguredOut &&
!figuredOutAllergens.Contains(allergen))
{
foreach (Allergen removeTarget in allergens.Where(x => x != allergen))
{
removeTarget.RemoveIngredient(allergen.MyIngredient);
}
figuredOutAllergens.Add(allergen);
finished = false;
}
}
}
HashSet <string> nonAllergenIngredients =
new HashSet <string>(uniqueIngredients);
foreach (Allergen allergen in allergens)
{
nonAllergenIngredients.ExceptWith(allergen.ingredientCollection);
}
int output1 = foods
.SelectMany(x => x.ingredients)
.Where(x => nonAllergenIngredients.Contains(x))
.Count();
Console.WriteLine($"The answer is: {output1}");
Console.WriteLine();
Console.WriteLine("Star 2");
Console.WriteLine();
Console.WriteLine($"The answer is: {string.Join(',', allergens.OrderBy(x => x.name).Select(x => x.MyIngredient))}");
Console.WriteLine();
Console.ReadKey();
}